Pehpettjal calendar



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. R. MASCHMANN PERPETUAL CALENDAR Filed Dec. 23. 1924 2 She'gts-Shefl 2 $1 nointoz fiudolalfldsdmaim,

a Rouwv Patented May 1, 1928.

UNITED STATES PATENT OFFICE.

RUDOLPH MASCKMANN, OF

PATEBBON, NEW JERSEY, ASSIGNOR OF ONE-HAL! TO rnnrn'ruu. oALEunAn. I

Application filed December 23, 1924. 7 Serial No. 757,745.

My invention has for its general object a fiat perpetual calendar which can easily and quickly set forany year from the beginning to the end of the present calendar time,

6 and yet is simple and economical to manufacture. A

The invention consists in its entirety of a back card having printed or produced on its face twelve sets of numbers to represent the days of the twelve months and a series of key numbers, and on its back a scale of numbers designating all the years to which reference may be desired and opposite each year the respective key number, andan ad justable card arranged to slideover the face of the back card, and formed with twelve openings to expose the respective sets of numbers designating the days of the month and apertures to expose therespective key numbers, the month openings being headed by the names of the respective months and the days of the week, and the arrangement and selection of numbers and parts being such that by simply adjusting the slide card so as to expose the key number corresponding to the year desired, the calendar will be properly set forthat year and the correct week day for any day in that year will be exhibited for reference.

understood, I shall first describe in detail the mode in which let present prefer to carry the invention into practice and then particularly point out its various features in the claims.

Reference is to be had to the accompanying drawing forming part of this specification in which the same parts are designated by like letters in all the figures. Figure 1 shows the face of a perpetual calendar embodying my invention, parts being broken away. i

igure 2 shows the face of back card of,

the same, the front slide card being removed.

Figure 3 shows the year and key numbering on the back of the back card.

In the drawings, 4' designates the back card of the calendar and 5 the front card mounted to slide on the face of the back card, the term card being herein employed 1 in the columns apply. 30 In order that my invention may be fully because cardboard is the material generally employed for these calendars, although of. course any other fiat thin plates of wood, metal or other material could be used for these cards.

Theslide card 5 is here shown kept to and ided on the back card 4, by means of a ace card 6 secured to the borders of the back card and overlapping the slide card, but it is evident that other equivalent keeping and guiding means may be employed in lieu thereof.

On the back of the back card there is inscribed a scale or table 7 of years and a key number "8 opposite each year the key numbers 8being shown in heavy type on Fig. 3' in columns immediately following the columns of year numbers, which are shown in light hype and are represented onlyby the last two 'igits of each year. This table 7 is divided into four sections by heav vertical lines A, and each section is divide into vertical columns by light vertical lines B in alternate columns in which are placed the light and heavy type figures of the said year and key numbers respectively. The heavy type blocks of Fig. 3 at the head of each section indicate centuries to which the year numbers 7 Thus the year number 25 in the second column of the first section, and its key number 2, horizontally adjacent thereto, in the next column taken in connection with the block of figures (l at the head'of the first section, refers to the year numbers 25, 425, 825, 1225, and 1625. In other words, the figures in each block C, refer to the centuries to which the year and key numbers below said block are applicable. For example; to set thecalendar for any of the years 201, 601, 1001, 99 1401 or 1801, we consult the third section, second horizontal row .andsecond figures down of the year and key number scale to find the key number 3 immediately following the year numbers 01. The slide card 5 is moved acrossthe back card 4, until i the key number 3 of the key scale 8 appears through the sight'aperture 11 formed on the slide card. The calendar is then properly adjusted to indicate correctly all 100 .ture 11. lVe then find that February the days of each Week and month for any of the common years 201, 601, 1001, 1401 or 1801.

It will be noted that the heavy type key numbers 8 on the scale table 7, line downwardly in vertical columns in cyclic order from 1 to 7, and that every leap year indicated in the light type figured columns by numbers divisible by 4, have two key numbers, one of which is to be used for the first two months of each year, and the other to be used for the remainder of the year. For convenience, these two key numbers are arranged in the heavy type column as fractions, with the understanding that for any given leap year, the numerator of the fraction corresponding thereto, is to be taken as the number of the scale 8 to be exposed under the aperture 11 for the first two months of the given leap year, and at the end of said two months, the slide 5 is to be shifted to expose the denominator of said fraction in aperture 11, in order to give correct calendar indications for the remaining months of the given leap year. For example, take the leap year 1976; under the seventh column in the fourth section on scale 7, we find the key number correspond ing to the year 1976 to be expressed as a fraction. For the months of January and February 1976, we shift the slide member to expose the numeral 3 of scale 8' in aper- 29. 1976, falls on Sunday, and that if we keep the scale member in this position, that March the 1st, of the same year also falls on a Sunday. This is due to the fact that the month of February section is numbered for common years or up to the 28th only. In order to correct the calendar for the remaining ten months of the year, it becomes necessary to shift the slide card so that the indication Mon, is directly over the numeral 1 of the March set of numbers. This is obviously effected by shifting the slide card up from the number 3 to the next scale number 4 to bring the number 1 under the legend Mon. It is to be noted that there are seven numbers on the scale 8, and that the distance bet-ween adjacent numbers thereof, are exactly equal to the distance between the numbers in each horizontal row of the month-indicating sets. Consequently, a shift of the slide scale from one number to the next on scale 8, also shifts the apertures of the slide card 5 over the months indicating sets from one vertical column of numbers to the next. Of course,

' it will be obvious, that when the numerator of the key fraction is 7, the denominator must be 1, because of the cyclic order on which the key numbers of the scale are of necessity arranged.

On the face of the stationary back card 4 are inscribed twelve sets of numbers 9 to designate by number the days of each month; and, preferably, above said sets there is a horizontal scale 8' of key numbers to which the key numbers 8 of the scale 7 (on the back of the back card) opposite the numbers designating the respective years correspond.

In the front slide card 5 are cut twelve openings 10, each adapted to surround and expose one of said sets 9; and an aperture 11 is also formed in card 5 to expose any one of the series of key numbers 8 of the key number scale 8 inscribed on the face of the back card 4.

The selection and arrangement of all the numbers, markings and arts is such that when the front slide car 5 is moved over the back card 4, so as to expose through the aperture 11 the key number 8 of the scale 8 corresponding to any desired common year as shown on the scale 7 on back of the back card, the calendar will bethen automatically set for that common year, and the week day of i any numbered day of an month in that year can be easily determined? It is evident that many changes ma be made in the form of my invention ere shown without departing from the boundaries of m invention as defined by the following 0 aims.

I claim as my invention:

1. A erpetual calendar comprising a back car havin inscribed thereon a set of numbers for eac month in the year, each set having the numbers thereof arranged in vertical and horizontal columns e ually spaced to indicate the numbers of eac day in the month, and having also inscribed thereon a horizontal scale provided with a series of key numbers spaced apart to correspond with the spacing of said vertical columns, a front card slidable over the back card and having openings therethrough to expose the res ective sets of month numbers, and inscri ed above each opening with the names of the respective months and days of the week, and also having an aperture adapted to expose onl one of the key numbers of said scale w en the front card is properly positioned to expose the sets of month numbers, the relative arrangement of number sets and scale on the back card and of openings and aperture on the front card being such that when the front card is positioned to expose a key number corresponding to anycommon year the sets of month numbers for that year will be properly exposed ,in said openings to form with the readings adjacent said openings a calendar for the year to which the key numbers relate, the said back card being provided with a table to indicate the particular key number of said scale corresponding to any given year.

2. A calendar as set forth in claim 1 in which the said table shows a single key number for any common year desired, and shows two of such members for each leap year arranged for convenience as numerator and denominator of a fraction, setting for leap years being effected by first moving the front card to expose the key number on said scale corresponding to the numerator of said fraction and retaining it so positioned during the first two inonths of said leap year and then moving said front 1 card to expose the same key number on said scale as the denominator of said fraction and retaining it in this position for the remainder of the year.

In testimony whereof I afiix my signature.

RUDOLPH MASCHMANN. 

